The Boxer is smoother, and its fuel economy while affected by how you drive, is not as affected by a lead foot as the turbo cars are. Mind you, driven properly, you can get really good mileage from the Turbo.

The 6-cylinder has a higher compression ratio, a dual plain intake, and adds the Active Valve-Lift system on top of the Active Valve-Control System that both have. This allows you to feel more power at lower RPM, where you need the 4-cylinder to get over 3,000 RPM for the Turbo to kick in and give you more power.

The 6-cylinder can run on regular gasoline (premium is just recommended) without harm to the engine, where the turbo RERQUIRES premium. Since both have the same EPA rating highway, and the turbo is only 1 MPG better city, the fuel economy is wash unless you run regular in the 3.0 and save a few dollars a tank full.

The turbo also sits 3/10ths of an inch higher off the ground, so the center of gravity is higher, just a little, which makes a difference at higher speeds when avoiding something or changing lanes for example.

If you prefer a manual tranny, then the GT does offer that option.

The 3.0 does share the Bilstein suspension from the Spec B, so the turning circle is a little larger than the GT.